Differential feeding mechanism for sewing machines



Jan. 22, 1935.

Filed Oct. 21, 1955 3 Sheets-Sheet 1 Jan. 22, 1935. MYERS 1,988,806

DIFFERENTIAL FEEDING MECHANISM FOR SEWING MACHINES Filed Oct. 21, 1953 5 Shets-Sheet 2 W iXneam Jan. 22, 1935. w. MYERS 1,988,806

Y DIFFERENTIAL FEEDING MECHANISM FOR SEWING MACHINES Filed Oct. 21, 1935 5 Sheets-Sheet 3 WW mm I Patented Jan. 22, I935 DIFFERENTIALFEEDING: MECHANISM ron E SEWING MACHINES fJalter'Myers, Bridgeport, Conn assignor toThe Singer" 'Manufacturing 1 Company, Elizabeth; S

a it. it, a corporation-of New Jersey PPl-ioationc-October 21, 1933-, Serial- No. 694,530

i This: invention relatest to improvements. .in. Workeadvancing or feeding mechanisms. for seiving. machines and has ior its object to provide .a

simple. and compact differential feedingnmecha anism which is particularly adaptedffornembodiment in a sewing machine work-arm .for

advancing. the worklengthwise of.-said -arm;.:.. 1

Withathe'above and other objectsinview, as:

willhereinafter appear, the invention. comprises the: devices, combinations, and arrangements of partszhereinafter set forth and illustrated: in the. accompanying drawings of a preferred. embodiment of theinvention, .from. .tvhi'ch the several features of the invention and-:the. advantages-rattained therebywill be readily understood by those skilled in the art.-

l frontelevation, partly insection, of a feed-off-arm sewing machine embodying. the

invention. Fig. 2 is a top planview of the ma.-.

chine with theheadatthe free end of the bracket-- arm broken Fig. 3 is a top plan-view of the Work-arm, with the covereplate.and1throat=plate removed. Fig. 4 represents .a vertical. section taken lengthwise and. substantially. centrally. of

the. sewing machine ..Work+ar;'n, and showing. in.

side elevation a portion: of .the bracketearm standard and portions of the needle-carryingbar and pressersdevice- Fig. 5 representsanenlarged transverse section. of I the. feed-bars substantially on the line. 5 .5 of'Fig. 4. .Fig.6 represents an enlarged transverse section of the feed-bars. substantially on the. line 66-of Fig.4. .Fig. :7. rep;-

resents an enlarged transverseasection. of the; 77 of Fig. Fig. perspective view. of thestud-bolt. connection between :the rock-lever uponthecmain.

feed-bars substantially onthe line feed-bar and thelink actuated thereby,

The present: difierential feeding mechanism is herein described and illustrated in the accompanying drawings, as embodied in a feed-off-arm sewing machine which is more fully disclosed in my prior U. S. patent application Serial- No. 627,489, filed Angus, 1932. Reference maybe made to said prior patent application'for an understanding of details of construction of the SEW-- .g machine not herein disclosed, but it is to be understood that the present invention is not-limited in all its aspects to saidspecific sewing Ina-- chine.

The sewing machine illustrated in the drawings has a frame comprising a bed including a forwardly extending arm 1 carrying a laterally'extending hollow arm 2 which, in turn, carries a rearwardly extending tubular and substantially straight work-arm 3. =Thearms 1, Zand 3 are needle-apertures 8. Rising froml'the 'i ramesioed', I

at the rearward portion or" thearm 1 is the:stand-; ard 9 :ot. a hollow bracket-arm 10 which; termi nates in a head. 11 overhanging the free end of the work-'supportingarm 3.:' i

Rotatably journaled I in the bracket-arm 110:: is a. horizontallydisposed main shaft 12 extending outside of the bracket-arm at. the right hand side thereof, theprojectingend oi said-shaft carrying a clip-belt pulley. 13anda driving-belt pulkey 14" with its. associated balance-wheels15;); At. its opposite end, the main shaft carriesia crank-. disk 16 operatively connected-in any usual :or suit--. able manner, as by means of a link 17,: witha vertically .reciprocatory needle barn 1'8;. The needle bar is j'ournaled for endwise reciprocation in suitable bearings provided -in;the*bracket -arm head 11, and in the present instance carries-at its lower end-a pair'ofneedles 1-9 A-lso j'our naled for vertical movement in the head-'11 the usual pre'sser-bar Zfi'carrying at itslower end: presser-foot 21. I. I 1

Disposed" within :and extending: lengthwise 50f the laterally extending 'hGHO-W' arnr 2 of: theframe i's an actuating shaft: 22 journa ld adjacent one endina bearing 23 in said arm- 21 The "shaft 22 enters and extends transversely across the-fonward end of- Work-armfi in-a direction substantiaily normal to the length of the work arm,

said shaft 22 being journald in a bearing 24 prosthereto in any. suitable .'manner., .said'l-belt-guard having a. removable side: cover. 28.

Carried by the actuating shaft 22'Lwithii1 the work-armfi arethe bevel-gears 29i-and-i3ikmeshing s with :bevel pinion's -3150f one the: size:

of. saidbeveli-gears. .1 The .pinions; :31 are .tcarried;

2 by horizontally disposed and parallel shaft-sections 32 suitably journaled in the work-arm 3 to extend lengthwise thereof. The shaft-sections 32 have universal joint connections with intermediate shaft-sections 33 connected in like manner with parallel shaft-sections 34 journaled in suitable bearings provided within the work-arm 3 at the free end thereof. At their rearward ends, the shaft-sections 34 carry bevel-gears 35 meshing with bevel-gears 36 (only one pair of gears 35, 36 being shown in the drawings) for driving the vertical-axis loop-takers 3'7in which'are journaled thread-cases 38. The loop-takers rotate twice for each complete reciprocation of the eedles l9 and cooperate therewith in the formation of lock-stitches, but it is to be understood that the present invention is not limited to any specific form of loop-taker mechanism, as it will be evident that it is also adapted, amongst others, for embodiment in a feed-off-arm machine having a chain-stitch looper mechanism, and particularly of the type disclosed in the pending U. S. patent application of A. B. Clayton, Serial No. 692,273, filed Oct. 5, 1933.

The work-advancing feeding mechanism comprises a main feed-dog 39 and an auxiliary feeddog 40 operating in the feed-slots '7 of the throatplate 5, the main feed-dog 39 being disposed rearward of the auxiliary feed-dog in the direction of seam formation. The main feed-dog 39 is secured by screws 41 upon the rearward end of a substantially-straight main feed-bar 42 extending lengthwise of the work-arm 3 and fulcrumed to rock and slide upon a pin 43 which is eccentric to its shank portion 44 rotatably adjustable in the fulcrum-block 45 suitably secured upon the bottom wall of the work-arm 3. At its forward end, the feed-bar 42 is formed with a vertical fork 46 embracing a split-block 4'7 on a feed-advance eccentric 48 which imparts endwise movements to the feed-bar. The eccentric 48 is adjustably secured upon the hub of the bevel-gear 30 in any suitable manner to provide for changing the length of feed of the work.

Secured to the side of the feed-bar 42 by screws 49 is a bar 50 which is formed with a horizontal fork 51 embracing a split block 52 on a feed-lift eccentric 53 secured upon the actuating shaft 22 within the work-arm 3. The eccentric 53 imparts rocking movements to the feed-bar 42 about the fulcrum-pin 43 to thereby raise and lower the main feed-dog 39. I

The auxiliary feed-dog 40 is secured by screws 54 upon the rearward ,end of an auxiliary feeddog carrier in the form of an auxiliary feed-bar 55' endwise slidable upon the main feed-bar 42 and also extending lengthwise of the work-arm 3. The feed-dog carrying end of the auxiliary feed-bar 55 is reduced inthickness and is guided by an L-shaped angle bracket 56 secured by screws 5'7 upon a side face of the main feed-bar 42 to overhang the auxiliary feed-bar 55, as illustrated in'Fig. 6 of the drawings. A similar L- shaped angle bracket. 58 is secured by screws 59 upon the main feed-bar to overhang and guide the forward end of the auxiliary feed-bar 55, which latter is confined against sidewise movement upon the main feed-bar by a retaining plate 60 secured by screws 61 upon the side of the main feed-bar opposite to that upon which the angle bracket 58 is secured, as illustrated in Fig. '7 of the drawings.

- Pivotally secured by a stud-screw 62 upon a side face of the auxiliary feed-bar 55 at a point between the angle brackets 56 and 58 is the rearward end of a link 63 of which the opposite or forward end is apertured to pivotally receive the cylindrical end 64 of a stud-bolt 65 which has an intermediate flattened portion 66 and is reduced and threaded at its opposite end. The flattened portion 66 of the stud-bolt is adjustably fitted into a guideway in the form of a segmental slot 67 provided in a furcation 68 of a bifurcated vertically disposed rock-lever 69, said stud-bolt 65 being secured in adjusted position in the slot 67 by a nut '70 and a washer '71. The other and shorter furcation '72 of the rock-lever is slidably guided by the side of the main feed-bar 42 opposite to that slidably guided by a thickened portion of the furcation 68 below the segmental slot 6'7. The furcation '72 is pivotally secured upon the main feed-bar 42 by a horizontally disposed stud-screw '73 and a lock-nut '74 to provide for rocking movements of the lever about an axis transverse to the direction of feed. The segmental slot 6'7 in the furcation 68 is of suflicient length to permit of adjustment of the stud-bolt 65 into horizontal alinement with the pivotal axis of the rock-lever 69, it being understood that the radius of curvature of the segmental slot 6'7 corresponds to the length of the link 63.

The lower arm of the rock-lever is preferably solid throughout the width thereof and its cylindrically rounded free end '75 is slidably and rockably disposed in a guideway provided by opposed lever-anchoring angle-brackets '76 suitably secured by screws '77 upon the bottom wall of the work-arm 3, whereby said brackets may be relatively adjusted to take up wear.

When the stud-bolt 65 connecting the rocklever 69 and link 63 is adjusted into horizontal alinement with the stud-screw '73, the main and auxiliary feed-bars are reciprocated in unison. However, when the stud-bolt 65 is adjusted upwardly above the pivotal axis of said rock-lever 69, it is evident that the rocking movements imparted to the anchored rock-lever upon endwise reciprocation of the main feed-bar 42 will be transmitted to the auxiliary feed-bar 55, whereby the auxiliary feed-dog 40 will have a greater amplitude of work-advancing movement than the main feed-dog 39.

Outstanding as an advantageous characteristic of the present differential feeding mechanism is the simplicity and sturdy nature of the construction, afforded by the direct connections of the main feed-bar with the actuating shaft with in the work-arm, and the described rock-lever and link connections with the auxiliary feed-bar. Furthermore, the present differential feeding mechanism is particularly well adapted for embodiment in a feed-ofi-arm machine having a Work-arm and a carrier-arm for the work-arm arranged coplanar, whereby the feed and looptaker actuating shaft may be advantageously disposed and driven in the manner herein described.

Having thus set forth the nature of the invention, what I claim herein is:-

1. A feed-off-arm sewing machine having a frame including a, bracket-arm, a substantiallystraight tubular work-arm extending under said bracket-arm in a direction out of parallelism with a vertical plane containing the longitudinal axis of said bracket-arm, and a, carrier for said workarm, stitch-forming mechanism, differentially movable main and auxiliary feed-dogs, a rotary actuating shaft disposed within said work-arm, means for rotating said shaft in a continuous direction,'and connections within said work-arm for imparting differentially timed work-advancing movements to said feed' dogs from said actu ating -shaftj Y 2. A feed-'oif-armsewing ma'chine having a frame including a bracketarm, a substantiallys'tr'aight tubular work-arm extending under said bracket-arm in a direction out of parallelism with a vertical plane containing the longitudinal axis of said bracket arm, and a carrier for said work; arm, stitch-forming, mechanism," differentially movable main andauxiliary feeddogs; a rotary actuating "shaft having one "enddisposed within and" extending CIOSSWiSGTOf' the'length :of said work-arm, means for-rotating said shaft in a continuous" direction, and connections within said work-arm for imparting differentially timed work-advancing movements to said feed dogs from said actuating shaft.

3. A feed-off armsewing machine having a frame including a bracket=arm, a substantiallystraighttubular work-arm having a free end extending under'saidbracket-arm, and a carrier, armforsaid work-arm offset laterally from said bracket-arm, stitch-forming mechanism, differentially 'movable, main and auxiliary feed-dogs, a rotary'shaft journaled in said carrier arm and extending into'one end of said work-arm, said rotary shaft being disposed substantially normal to the length of'saidwork-arm, means for'rotating said shaft in a continuous direction, and connections within said work-arm for imparting differentially timed work-advancing movements to said feed-dogs from said actuating shaft.

4. A feed-oif-arm sewing machine having a frame including a bracketearm', a horizontally disposed work-arm having a free end extending under said bracket-arm, and a horizontally disposed work-arm carrier arm substantially coplanar with said work-arm, stitch-forming mechanism, differentially movable main and auxiliary feed-dogs, a rotary shaft 'journaled' in sai'd carrier arm and disposed substantially normal to the length of said work-arm, means for actuatingsaid shaft, and connections within said work-arm for imparting diiferentially' timed work-advancing movements to said feed-dogs from said actuating shaft.

5. A sewing machine comprising a, frame having a bed formed with a forwardly extending arm, a laterally extending arm carried by'said forwardly extending'arm, a rearwardly extending work-supporting arm carried by and sub stantially coplanar with saidlaterallyextendingarm,.a bracket-arm rising from the rearward end of said forwardly extending arm andter-minatingat its free end in ahead overhanging the free end. of said work-supporting arm, a shaft, journaled horizontally in said bracket-arm, a reciprocatory'needle connectedto bedriven by said shaft, a. second shaft journaled in said laterally extending arm. inparallelismfi with said first mentioned shaft, an operative connection between said shafts', loop-taking mechanism in said work-supporting arm,'operative connections for actuating said loop-taking mechanism from said second shaft, and main and auxiliary feeddog carriers differentially reciprocable within said work-supporting arm, said feed-dog carriers deriving operative movements from said-second shaft.

6. A sewing machine having a frame including a bracket-arm, a substantially straight tubular work-arm having a free end extending under said bracket-arm, and a carrier arm for said work-arm offset laterally from said bracket-arm, stitch-forming mechanism, a feed-bar in said work-arm, a feed d'ogcarried 'by said feed bar, an actuating shaft operatively connected" to said feed-ban forimpartingr work-advancing i move ments tosai'd feed -dog in a direction lengthwise of saidwoi k arm, said actuating shaft J being disposed within and" transversely of the length of the work-arm, means for actuating said shaft, an auxiliary feed-dog, and means disposed in said work-arm for imparting work-advancing movements to saidauxiliary feed-dog from said feed bar. 7

"7. A feed oiT-arm sewing machine having a frame including a bracket arm, a substantiallystraight'tubular work-arm having a free end extending under said'bracket arm, and a carrierarm for saidwork-arm, stitch-forming mechanism, a feed-bar extending lengthwise of saidwork-arm, a main feed-dog carried by said feed-- bar adjacent to the free end of said-work-arm, a rotary shaft 'j'ou-rnale'd in said carrier-arm and extending intosaicl work-arm transversely of the length of the work-arm means for rotating said shaft, anactuating member'carried by'said shaft within the work-arm and operatively' engaging saidfeed barfor imparting work-advancing and return -moveinents to said main feed-dog, an actuating member carried by said shaft'wi'thin the work-arm for raising and lowering the feedbar, an auxiliary feed-dog disposed adjacent and movable differentially with respect to'said main feed-dog, and means disposed in said work arm for actuating said auxiliary feed-dog from said feed-bar;

8. A feed-off-arm sewing machine-having a frame including a bracket-arm, horizontallydisposed substantially straight work-arm having a free end extending under said bracket-arm, and a horizontally disposed work-arm carrier arm substantially coplanar with said work-arm, a main feed-clog carrying bar in said work-arm, a rotary shaft'journaled in said carrier arm, means for imparting work-advancing movementsto'said main feed-bar from said rotary shaft, an auxiliary feed-dog carrying barslidably dis-- posed upon said main feed-bar, and means oper- J atedby said main feed bar for actuating said auxiliary feed-bar differentially withv respect to said'main feed-bar in the direction of the length ofsaid work-arm.

9. A feed-oif-arm sewing machine having" a frame including a'bracketarm,.an arm extending forwardly'from said bracket-arm, a laterally extendingarm carried by the forwardly extending arm, and a rearwardly extendingwork-arm carried by and substantially coplanar 'with'sa-id laterally extending arm, stitch-forming mechanism, dilferenti'ally movable main and auxiliary feed-dogs in said work-arm, and means for imparting differential work-advancing movements to said feed-dogs including actuating mechanismsupported by said laterally-eXtending-arm and operatively connected to said feed-dogs;

10; A sewingmachinehavinga bracket-arm, a tubular work-arm having a suspended free" end extending under said bracket-arm, a needle carrying member'supported by said bracket-arm, a rotaryneedle-thread-lbop taker j'ournaled within said work-arm, main and auxiliary feed-dogs at the free end of said work-arm, actuating mechanismhoused within said tubular work-arm for rotating said loop taker in'a continuous direction, and feed-actuating connections housed within said work-arm for imparting differential work-advancing movements to said main and auxiliary feed-dogs.

11. A feed-ofi-arm sewing machine having a bracket-arm, a substantially-straight tubular work-arm extending under said bracket-arm in a direction out of parallelism with a vertical plane containing the longitudinal axis of said-bracketarm, a carrier arm for said work-arm, a recipro catory needle, mechanism carried by said bracket-arm for reciprocating said needle, a rotary needle-thread-loop taker journaled within said work-arm at the free end thereof, main and auxiliary feed-dogs at the free end of said work-arm, a rotary shaft supported by said carrier arm, means for rotating said shaft, and mechanism operatively connected to said rotary shaft and extending lengthwise of said work-arm for rotating said loop taker in a continuous direction and for imparting differential work-advancing movements to said main and auxiliary feed-dogs.

12. Differential feeding mechanism for sewing machines comprising diflerentially movable main and auxiliary feed-dogs, a feed-bar carrying said main feed-dog, means for actuating said feedbar to impart operative work-advancing movements to said main feed-dog, an auxiliary feeddog carrier, and means for imparting work-advancing movements to said auxiliary feed-dog from said feed-bar comprising, a lever pivotally mounted between its ends upon said feed-bar and having oppositely directed arms extending transversely of the direction of feed, anchoring means engaging one arm of said lever to limit the movement of one end of the lever, and a link connecting the other arm of said lever and said auxiliary feed-dog carrier.

13. Differential feeding mechanism for sewing machines comprising differentially movable main and auxiliary feed-dogs, a feed-bar carrying said main feed-dog, means for actuating said feed-bar to impart operative work-advancing movements to said main feed-dog, an auxiliary feed-dog carrier, and means for imparting work-advancing movements to said auxiliary feed-dog from said feed-bar comprising, a lever pivotally mounted.

between its ends upon said feed-bar and having oppositely directed arms extending transversely of the direction of feed, anchoring means engaging one arm of said lever to limit the movement of one end of the, lever, and an adjustable connection between the other arm of said lever and the auxiliary feed-dog carrier.

14. In a sewing machine having a horizontally disposed tubular work-arm, a feed-bar disposed within and extending lengthwise of said workarm, a main feed-dog carried by said feed-bar, means for actuating said feed-bar to impart operative work-advancing movements to said feeddog, an auxiliary feed-dog carrier disposed within said work-arm, and means for imparting workadvancing movementsto ,said auxiliary feed-dog from said feed-bar comprising a vertically disposed two-armed lever pivotally mounted between its ends upon said feed-bar, anchoring means engaging the lower arm of said lever to thereby influence the amplitude of movement of the upper arm of the lever upon reciprocation of said feed-bar, and an adjustable connection between the upper arm of said lever and the auxiliary feed-dog carrier.

15. In a sewing machine having a horizontally disposed tubular work-arm, a main feed-bar disposed within and extending lengthwise of said work-arm, a main feed-dog carried by said feed bar, means for actuating said feed-bar to impart operative work-advancing movements to said main feed-dog, an auxiliary feed-dog carrier slidably mounted upon said main feed-bar, a verticallydisposed two-armed lever pivotally mounted between its ends upon said main feed-bar, the upper arm of said lever having a segmental guideway intersecting the pivotal axis of the lever, a link having one end secured for adjustment in said guideway and its other end operatively connected to said auxiliary feed-dog carrier, and means operatively anchoring the lower arm of said lever to said work-arm, whereby rocking movements are imparted to said lever upon reciprocation of the main feed-bar lengthwise of the work-arm.

16. Differential feeding mechanism for sewing machines comprising differentially movable main and auxiliary feed-dogs, a feed-bar carrying said main feed-dog, means for actuating said feedbar to impart operative work-advancing movements to said main feed-dog, an auxiliary feeddog carrier supported by said feed-bar for movement relative thereto, a lever pivotally mounted upon said feed-bar for rocking movements about an'axis transverse to the direction of feed, an operative connection between said lever and the auxiliary feed-dog carrier, and fixed lever-anchoring means providing a guideway confining therein one end of said lever, to thereby compel rocking movements of the lever upon actuation of said feed-bar in the direction of feed.

17. Differential feeding mechanism for sewing machines comprising differentially movable main and auxiliary feed-dogs, a feed-bar carrying said main feed-dog, means for actuating said feed-bar to impart operative work-advancing movements to said main feed-dog, an auxiliary feed-dog carrier supported by said feed-bar for movement relative thereto, a lever pivotally mounted upon said feed-bar for rocking movements about an axis transverse to the direction of feed, said lever having a rounded end, an operative connection between said lever and the auxiliary feed-dog carrier, and relatively adjustable anchoring brackets confining therebetween said rounded end of the lever for limited rocking and sliding movement.

18. In a sewing machine having a horizontally disposed tubular work-arm, a main feed-bar supported in said work-arm for endwise reciprocatory and for rocking movements, said feed-bar extending lengthwise of the work-arm, a main feed-dog carried by said feed-bar, means for actuating said feed-bar, an auxiliary feed-dog carrying bar slidably supported by said main feedbar, a vertically disposed bifurcated lever embracing said main feed-bar and having one of its furcations pivotally secured upon said main feed-bar for rocking movements of said lever about an axis transverse to the direction of feed, the other furcation of said lever having a segmental guideway extending upwardly from the pivotal axis of the lever, a link having one end adjustably secured in said guideway and its other end operatively connected to said auxiliary feedbar, and anchoring means engaging said lever below the pivotal axis thereof.

WALTER MYERS. 

